INCREASE OF CROPS BY USE OF FERTILIZERS 15 



when the crop is well fertilized with nitrogen compounds ; 

 it requires to have a controlled plot side by side to be able 

 to draw attention to the result. It is generally on the heavy 

 clay soils, deficient in both lime and phosphates, that basic 

 slag has produced most obvious and marked results. It is 

 one of the most striking scenes, on a clear day, at certain 

 seasons of the year, to ascend the tower at Cockle Park, look 

 over the experimental plots on the farm, and observe the 

 extraordinary variety of colour that meets the eye, due to 

 the different treatment the plots have received. Those 

 receiving liberal dressings of phosphates are brilliantly green, 

 while those that have been badly treated are a dull, unhealthy 

 yellow. It is an old farming tradition that pastures are 

 improved by grazing with stock that receive generous rations 

 of rich food in addition to what they pick up for themselves; 

 chemical fertilizers can produce the improvement in less 

 time and at less cost. The relative importance of phos- 

 phatic manures to nitrogenous and potassic manures on cer- 

 tain types of soil is best described by quoting Gilchrist's 

 comments in the Cockle Park " Guide to Experiments for 

 1918 " : " On the great bulk of poor pastures on the heavy 

 soils of Northumberland, basic slag is the most effective 

 manure for economic improvement, and on the lighter soils 

 the same manure, along with a potash manure, has also been 

 found to be most effective. The question has also been 

 settled that second and even up to sixth dressings of slag are 

 quite as effective as first dressings. The after-effects of 

 feeding cake to grazing stock are far from proving as satis- 

 factory as was expected." 



" For old land hay active nitrogenous manures have been 

 shown to deteriorate greatly the feeding value of the hay, 

 while phosphatic manures, combined with potash manures 

 if necessary, have greatly developed clover and improved the 

 feeding value of the hay. In combination with dung, slag 

 has been found to be the best artificial dressing for old land 

 hay, probably because the dung contains sufficient nitrogen 

 and potash, while slag supplies phosphates and lime in suffi- 

 cient quantities and in a suitable condition to act with dung. 



